首先先看内核链表的定义:linux-/include/linux/list.h
struct list_head {
struct list_head *next, *prev;
};
看出来内核链表(循环表)只有前驱和后继指针,没有数据域,这是和一般的单双链表的区别
示意图:初始化链表:
#define LIST_HEAD_INIT(name) { &(name), &(name) }
#define LIST_HEAD(name) \
struct list_head name = LIST_HEAD_INIT(name)
LIST_HEAD(name)相当于struct list_head name = LIST_HEAD_INIT(name)={ &(name), &(name) } 定义并初始化了前驱和后继指针。等于下边
struct list_head {
struct list_head *next, *prev;
}head={&(head),&(head)} 就是一般的结构体定义并初始化。
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添加节点:
static inline void __list_add(struct list_head *newer,
struct list_head *prev,
struct list_head *next)
{
newer->next = next;
newer->prev = prev;
next->prev = newer;
prev->next = newer;
}//插入节点操作
static inline void mlist_add(struct list_head *newer, struct list_head *head)
{
__list_add(newer, head, head->next);
}//头插法,遍历时数据逆序
static inline void mlist_add_tail(struct list_head *newer, struct list_head *head)
{
__list_add(newer, head->prev, head);
}//尾插法,遍历时数据正序
代码:
#include<string.h>
#include<stdlib.h>
#include<stdio.h>
#include"list.h"
typedef struct _stu
{
char name[20];
int num;
struct list_head list;
}stu; //定义了宿主结构体stu 在宿主结构体中定义了struct list_head的变量list
int main()
{
stu *pstu;
stu *tmp_stu;
struct list_head stu_list; //定义了头节点
struct list_head *pos;
int i = 0;
INIT_LIST_HEAD(&stu_list); //对头节点进行初始化
pstu = malloc(sizeof(stu)*5); //对宿主结构体申请空间
for(i=0;i<5;i++)
{
sprintf(pstu[i].name,"Stu%d",i+1); //格式化数据写进成员变量name中
pstu[i].num = i+1;
mlist_add_tail( &(pstu[i].list), &stu_list);//尾插法
//mlist_add( &(pstu[i].list), &stu_list); //头插法
} //对宿主结构体初始化并添加到以stu_list为头节点的链表中
list_for_each(pos,&stu_list) //?
{
tmp_stu = list_entry(pos, stu, list);
printf("student num: %d\tstudent name: %s\n",tmp_stu->num,tmp_stu->name);
}
mlist_del(&(pstu[4].list)); //删除的节点
printf("使用list_del()删除pstu[3]\n");
list_for_each(pos,&stu_list)
{
tmp_stu = list_entry(pos, stu, list);
printf("student num: %d\tstudent name: %s\n",tmp_stu->num,tmp_stu->name);
}
mlist_move(&(pstu[2].list),&stu_list); //删除节点再头插进去
printf("把pstu[2]移至head和head->next两个指针所指向的结点之间\n");
list_for_each(pos,&stu_list)
{
tmp_stu = list_entry(pos, stu, list);
printf("student num: %d\tstudent name: %s\n",tmp_stu->num,tmp_stu->name);
}
mlist_move_tail(&(pstu[1].list),&stu_list); //删除节点再尾插进去
printf("把pstu[1]移至head和head->prev两个指针所指向的结点之间\n");
list_for_each(pos,&stu_list)
{
tmp_stu = list_entry(pos, stu, list);
printf("student num: %d\tstudent name: %s\n",tmp_stu->num,tmp_stu->name);
}
free(pstu);
return 0;
}